I agree with everything you stated except for the above as I believe your statement is PADI specific (perhaps some other agencies as well). NAUI, as you may know, MSD is an actual course and is a perquisite to advance on to professional level training such as Dive Master, Assistant Instructor, and Instructor. I will say though that for someone that does not plan to go on to professional level certification within NAUI, the MSD certification does not offer a diver much beyond a better understanding of factors that affect diving, diving environments, and dive theory....it doesn't allow a diver to do anything they could not do if they already poses Open Water, Advanced, and Nitrox. The NAUI MSD course does provide training on search and recovery, and some rescue training as well. It is a good course for the diver that is interested in increasing their knowledge about diving science and recreational diving planning.
As one who is certified as a NAUI MSD and PADI Divemaster, I can state 2 things....the quality of the instructor has everything to do with the quality of the course and the certification, and PADI's Divemaster course pales in comparison to NAUI MSD with regards to expected knowledge and skills. If one was to complete the NAUI MSD certification with a good instructor that has high standards, they will be well prepared and have an easy time with the PADI Divemaster curriculum....not so much the other way around.
The fact is that the NAUI MSD certification sorta lives in the shadows of PADI's MSD program....even on ScubaBoard whenever the topic of MSD comes up, the posts are invariably referring to PADI's program...and because PADI's program is kinda of fluff and ego fodder, NAUI's MSD certification is often inadvertently (and ignorantly) painted the same.
-Z